In a mobile communication environment, a contention-based uplink bandwidth request process is needed for a mobile station to request that a base station provide an emergency service or an emergency data delivery service. If a plurality of mobile stations makes an uplink bandwidth request in the same time interval, collisions may occur between mobile stations. If no response is received from the base station even though the bandwidth request has been made, since it is assumed that collisions have occurred, the mobile station retransmits a bandwidth request to the base station.
Meanwhile, if a mobile station desires to request that a base station provide a desired service under the circumstance that the mobile station has been registered in the base station, a necessary bandwidth is assigned to the mobile station through a contention-based uplink bandwidth request process and multi-step procedures for setting specific services should additionally be implemented.
However, in the case where a service requested by the mobile station is an emergency service or emergency data delivery service, if an emergency call connection is delayed due to collisions of the bandwidth request or complicated procedures required for a service providing process, serious problems may arise. Furthermore, bandwidth request information may be re-transmitted because a bandwidth request using a ranging channel is made based on contention as described above. Therefore, wireless resources, such as power resources and frequencies of a mobile station, may be wasted and data transmission may be delayed.